EVAP codes and fuel cap - 2017 Dodge Ram 2500 4x4 6.4 hemi

[Ryan Poulos]

I have a 2017 Dodge Ram 2500 4x4 with a 6.4 hemi. It has 338,000 miles. Yes, high.
Its throwing 3 codes for EVAP leaks, and I replaced the gas cap and the code still comes up after reset.
Regarding the EVAP leak, does anyone have a diagram of components to the system? What should I 100% replace?
On the gas cap that I replaced, what else should I check? I did lube the new cap rubber seal and its clicking when tight. Thank you.

 

[1999 White C5 Coupe]

I have a 2017 Dodge Ram 2500 4x4 with a 6.4 hemi. It has 338,000 miles. Yes, high.
Its throwing 3 codes for EVAP leaks, and I replaced the gas cap and the code still comes up after reset.
Regarding the EVAP leak, does anyone have a diagram of components to the system? What should I 100% replace?
On the gas cap that I replaced, what else should I check? I did lube the new cap rubber seal and its clicking when tight. Thank you.

Post the codes.

 

[Ryan Poulos]

 

[Ryan Poulos]

I reset the codes and after starting this it came right back up with ‘Check Fuel Cap’ and the same 2 codes. P0456. P0457.

 

[tones2SS]

I had my gas tank and all accessories in the gas tank replaced. That was the only way that it got fixed.
Zero cost too because it's an emissions issue. That was on my 2005 GoMango Ram rcsb.

 

[RamRod37]

Only way your going to be able to fix the issue with out throwing parts at it is to have the evap system smoked to find the leak could be broken evap hose or it could be a purge or vent valve not closing all the way. I will not even try to diagnose a Evap system without smoking the system first and running open\close cycling test on valves.

 

[Ryan Poulos]

Guess I’ll have it smoke tested.

 

[Ryan Poulos]

Really quick. I reset the codes and the Evap codes did not come back up. However Gas cap is still coming up. Its a new gas cap from Oreillys. Not OEM Dodge. Could be the new (not OEM) gas cap?

 

[RedSRT4Me]

I think I spent maybe $100 in total for the 5.7 version of the emissions parts. Included, gas cap, evap purge valve and leak detection pump. All simple plastic. Evap purge is on the intake manifold, leak detection is on top rear passenger side of the tank.

 

[burner71]

I used to get these alot. The fix was replacing the purge valve. 12 bucks

 

[Ryan Poulos]

So were you guys getting ‘replace fuel cap’ because of the other bad evap items?

 

[burner71]

i would get the small evap leak code and the gas cap on the dash

 

[tones2SS]

Do the smoke test.
I had 2 smoke tests done, nothing showed, that's why they replaced the gas tank and all parts inside. One test at the dealership, one test done at my buddy's shop.

Buy an OEM gas cap and reset, drive around for about 100 miles. If it doesn't stay off, you have a problem.
Good luck man.

 

[Ryan Poulos]

I used to get these alot. The fix was replacing the purge valve. 12 bucks

I watched a bunch of youtube videos past night with my same issue. 99% fixed it with a purge valve. $16 at my local parts store. Im doing it once it stops raining. Crossing fingers.

 

[Jeff Strader]

Most likely it is the EVAP Canistor that is attached to the gas tank itself. The fittings sometimes leak and or the nipples that the lines attach to break off from the canistor. Been there and done that more than once.

 

[Ryan Poulos]

So Im ending the thread here on a good note. After replacing the purge valve, resetting codes, and then driving maybe 20 miles….boom…no check engine light on, no check fuel cap on…..problem fixed. Thanks for everyone on helping a brother out!!!

 

[tones2SS]

So Im ending the thread here on a good note. After replacing the purge valve, resetting codes, and then driving maybe 20 miles….boom…no check engine light on, no check fuel cap on…..problem fixed. Thanks for everyone on helping a brother out!!!

Awesome man.
Good luck!

 

[slbenz600]

i would get the small evap leak code and the gas cap on the dash

I have fought this problem for 50,000 miles, one dealer pressurized the system with smoke overnight never lost any pressure when the hose was removed smoke came out. Don’t let anyone tell you that OEM is better than aftermarket they are blowing sunshine up your kester. Good luck Ram won’t help because no one has ever had this problem BS.

 

[Gwerner74]

I have fought this problem for 50,000 miles, one dealer pressurized the system with smoke overnight never lost any pressure when the hose was removed smoke came out. Don’t let anyone tell you that OEM is better than aftermarket they are blowing sunshine up your kester. Good luck Ram won’t help because no one has ever had this problem BS.

Are you still dealing with the 0456, 0457 codes and gas cap error? I just solved the same issue on my 2015 6.4L. It was the Evap Leak Detection Valve on the canister. Tried 3 different Dorman units (Part number 310-218) and while they all cleared the codes, I then couldn't get gas in the tank without the pump shutting off. Put in a Duralast valve (Pat number ESM1000) and that solved both problems.

The Dorman valve is a completely different design internally than the OEM and Duralast version. Not sure if that contributed to the problem. Dorman part on top, Duralast on bottom.

 

[Ken226]

I have fought this problem for 50,000 miles, one dealer pressurized the system with smoke overnight never lost any pressure when the hose was removed smoke came out. Don’t let anyone tell you that OEM is better than aftermarket they are blowing sunshine up your kester. Good luck Ram won’t help because no one has ever had this problem BS.

I had this issue once due to scratches on the metal filler neck, right about where the gas cap o-ring seals against the metal.

The smoke testing system uses a adapter to seal against the filler neck, but it doesn't have click type torque limiter, so the tech can easily torque the adapter on enough to create a seal, that isn't possible with the gas cap.

Not saying this is your issue, but it was mine. I polished the scratches out with some 600 grit sandpaper, then went over it again with 1200 grit.

That was like, 2019. The problem hasn't come back.

It may not be your issue, but it's worth a look.